@jinxonik / UniLecs #240

version_compare.cpp

#include <iostream>
#include <string>
#include <vector>

void string_to_int_vector(const std::string s, std::vector<int>& vec)
{
  for (size_t start = 0, end = 0; end < std::string::npos; start = end + 1) {
    end = s.find('.', start);
    size_t len = end - start;
    vec.push_back(std::stoi(s.substr(start, len)));
  };
}

int version_compare(const std::string a, const std::string b)
{
  std::vector<int> vec_a, vec_b;
  string_to_int_vector(a, vec_a);
  string_to_int_vector(b, vec_b);

#ifdef __cpp_lib_three_way_comparison  // check for C++20 feature supported by library
  auto comp = (vec_a <=> vec_b);
  if (comp == std::strong_ordering::greater) { return 1; }  // a > b
  if (comp == std::strong_ordering::less) { return -1; }    // a < b
#else
  size_t min_size = std::min(vec_a.size(), vec_b.size());
  for (size_t i = 0; i < min_size; ++i) {
    if (vec_a[i] > vec_b[i]) { return 1; }   // a > b
    if (vec_a[i] < vec_b[i]) { return -1; }  // a < b
  }
  if (min_size < vec_a.size()) { return 1; }   // a > b
  if (min_size < vec_b.size()) { return -1; }  // a < b
#endif
  return 0;  // a == b
}

int main()
{
  std::vector<std::pair<std::string,std::string>> version_pairs = {
    {"5.05", "5.005"}, {"5.005", "5.05"},
    {"7.0.1", "7"}, {"7", "7.0.1"},
    {"5.1.2.4", "5.1.3"}, {"5.1.3", "5.1.2.4"}
  };

  for (const auto& s : version_pairs) {
    std::cout << s.first << " <=> " << s.second << " : " << version_compare(s.first, s.second) << std::endl;
  }
}

version_compare.py

def compare_version(a, b):
  aa = list(map(int, a.split('.')))
  ab = list(map(int, b.split('.')))

  min_len = min(len(aa), len(ab))
  for i in range(min_len):
    if aa[i] > ab[i]: return 1
    if aa[i] < ab[i]: return -1
  if min_len < len(aa): return 1
  if min_len < len(ab): return -1
  return 0

for v in (
    ("5.05", "5.005"), ("5.005", "5.05"),
    ("7.0.1", "7"), ("7", "7.0.1"),
    ("5.1.2.4", "5.1.3"), ("5.1.3", "5.1.2.4")):
  print(f"{v[0]} <=> {v[1]} : {compare_version(v[0], v[1])}")

version_compare.rb

def compare_version(a, b)
  a.split('.').map{ |s| s.to_i } <=> b.split('.').map{ |s| s.to_i }
end

for v in [
    ["5.05", "5.005"], ["5.005", "5.05"],
    ["7.0.1", "7"], ["7", "7.0.1"],
    ["5.1.2.4", "5.1.3"], ["5.1.3", "5.1.2.4"]]
  print "#{v[0]} <=> #{v[1]} : #{compare_version(v[0], v[1])}\n"
end

version_compare2.cpp

#include <iostream>
#include <string>
#include <vector>

void string_to_int_vector(const std::string s, std::vector<int>& vec)
{
  int n = 0;
  for (const char ch : s) {
    if (ch == '.') {
      vec.push_back(n);
      n = 0;
    } else if (ch >= '0' && ch <= '9') {
      n = n * 10 + (ch - '0');
    }
  }
  vec.push_back(n);
}

int version_compare(const std::string a, const std::string b)
{
  std::vector<int> vec_a, vec_b;
  string_to_int_vector(a, vec_a);
  string_to_int_vector(b, vec_b);

#ifdef __cpp_lib_three_way_comparison  // check for C++20 feature supported by library
  auto comp = (vec_a <=> vec_b);
  if (comp == std::strong_ordering::greater) { return 1; }  // a > b
  if (comp == std::strong_ordering::less) { return -1; }    // a < b
#else
  size_t min_size = std::min(vec_a.size(), vec_b.size());
  for (size_t i = 0; i < min_size; ++i) {
    if (vec_a[i] > vec_b[i]) { return 1; }   // a > b
    if (vec_a[i] < vec_b[i]) { return -1; }  // a < b
  }
  if (min_size < vec_a.size()) { return 1; }   // a > b
  if (min_size < vec_b.size()) { return -1; }  // a < b
#endif
  return 0;  // a == b
}

int main()
{
  std::vector<std::pair<std::string,std::string>> version_pairs = {
    {"5.05", "5.005"}, {"5.005", "5.05"},
    {"7.0.1", "7"}, {"7", "7.0.1"},
    {"5.1.2.4", "5.1.3"}, {"5.1.3", "5.1.2.4"}
  };

  for (const auto& s : version_pairs) {
    std::cout << s.first << " <=> " << s.second << " : " << version_compare(s.first, s.second) << std::endl;
  }
}

version_compare2.py

def compare_version(a, b):
  aa = list(map(int, a.split('.')))
  ab = list(map(int, b.split('.')))

  for i in count(0):
    if len(aa) <= i and len(ab) <= i: return 0
    if len(aa) <= i: return -1
    if len(ab) <= i: return 1
    if aa[i] < ab[i]: return -1
    if ab[i] < aa[i]: return 1

for v in (
    ("5.05", "5.005"), ("5.005", "5.05"),
    ("7.0.1", "7"), ("7", "7.0.1"),
    ("5.1.2.4", "5.1.3"), ("5.1.3", "5.1.2.4")):
  print(f"{v[0]} <=> {v[1]} : {compare_version(v[0], v[1])}")